Timm Matthew J, Leung Lydie, Anggara Kelvin, Polanyi John C
Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, Toronto, ON, Canada.
Commun Chem. 2021 Feb 12;4(1):14. doi: 10.1038/s42004-021-00453-x.
In Surface-Aligned-Reactions (SAR), the degrees of freedom of chemical reactions are restricted and therefore the reaction outcome is selected. Using the inherent corrugation of a Cu(110) substrate the adsorbate molecules can be positioned and aligned and the impact parameter, the collision miss-distance, can be chosen. Here, substitution reaction for a zero impact parameter collision gives an outcome which resembles the classic Newton's cradle in which an incident mass 'knocks-on' the same mass in the collision partner, here F + CF → (CF)' + (F)' at a copper surface. The mechanism of knock-on was shown by Scanning Tunnelling Microscopy to involve reversal of the CF umbrella as in Walden inversion, with ejection of (F)' product along the continuation of the F-reagent direction of motion, in collinear reaction.
在表面对齐反应（SAR）中，化学反应的自由度受到限制，因此反应结果是可选择的。利用Cu(110)衬底固有的起伏，吸附分子可以被定位和排列，并且可以选择碰撞参数，即碰撞未命中距离。在这里，零碰撞参数碰撞的取代反应产生的结果类似于经典的牛顿摆，其中一个入射质量在碰撞伙伴中“撞击”相同质量，在这里是铜表面上的F + CF → (CF)' + (F)'。扫描隧道显微镜显示，在共线反应中，撞击机制涉及CF伞状结构的反转，如同瓦尔登反转一样，(F)'产物沿着F试剂运动方向的延长线射出。
